This is a review of food dye toxicity per official EFSA reports and other studies since 2008.
Prenatal exposure to mixtures of food dyes can damage spatial working memory, and may affect brain signaling. There is evidence that the various colors interact causing a synergistic effect.
Tartrazine (Yellow 5) can activate estrogen receptors as a “zenoestrogen,” which may increase the risk of primary cirrhosis of bile ducts in postmenopausal women.
Tartrazine given for 30 days to rats and mice can induce neurotoxicity, learning deficits, and memory problems. The results are dose-dependent.
Sunset Yellow (Yellow 6) has been shown to reduce the size of testes in rodents, even at lower amounts than used in earlier studies.
Erythrosine (Red 3) can damage the thyroid gland — even causing thyroid tumors — because it contains four iodine atoms.
The blue colors (Blue 1, Blue 2) have been proven to be absorbed directly into the blood via shaved skin (such as when using a blue aftershave lotion), as well as through the mouth (as in eating a lollipop).